Unit 3: Reasoning and Explaining (MP2 and MP3)

3.4.3 Students Share with Class and Revise

Step 4: Students share work with the whole class then revise

Students were asked to explain to the class their individual solutions. This experience allows for rehearsing their argument and opening it up to questioning. The public sharing also gives the students an opportunity to view multiple representations and strategies, and rehearse the class definitions of odd and even. This activity prepared students for a follow-up activity in which they would make a group poster that included several strategies, representations, and public definitions.

Lorena’s Solution

Lorena knew the total was 9 flowers. She knew that 3 + 3 + 3 = 9, so she arranged three groups of 3 pens. 3 is an odd number.

She knew there were more tulips than roses, and more roses than lilies, so there could not be the same number of each flower.

She took 2 pens from one group of 3 and added them to another group of 3, which made 5 tulips + 3 roses + 1 lily = 9 flowers in the arrangement.

Daniela’s Solution

Daniela uses her fingers as a tool. She begins by putting out nine fingers and then adjusts the numbers of fingers to meet the constraints of the problem.

Jessica’s Solution

Many students, including Jessica, used tally marks to decontextualize the problem.

Other students decontextualized the problem using lists of odd numbers and cubes, and then used drawings of flowers to re-contextualize their solution.